Two cases of glioblastoma involving orbit and maxillary sinus are presented. Case 1: A 49-year-old male was admitted on May 20, 1982, with complaints of headache and impairment of memory. On July 27, 1982, operation was carried out. The tumor in the left temporal lobe was totally removed, and he subsequently received chemotherapy and irradiation. The postoperative course was uneventful. On Oct. 26, 1983, he was readmitted with complaints of disturbance of gait and memory. A CT scan revealed no local recurrence of the tumor but a diffusely enhanced mass in orbit and maxillary sinus. Reoperation was carried out on Nov. 10, 1983. No recurrence was seen at the original site where the first operation was done. The dura was intact so far as observed from inside and was protruding into the cavity from the side of the sphenoidal ridge. The tumor showed destructive growth to orbit and maxillary sinus. He died on May 20, 1984. The autopsy was refused. Case 2: A 33-year-old male was admitted on Oct. 24, 1981, with complaints of headache, vomiting and impairment of memory. A CT scan revealed a right temporal mass lesion. He was operated on three times, on Oct. 27, 1981, Feb. 23, 1984 and Sep. 6, 1984, respectively. He also received chemotherapy and irradiation. Finally, a CT scan revealed the recurrence of the tumor in the right frontal, temporal, parietal lobe and basal ganglia, and an invasion into orbit on a CT scan. He died on Nov. 26, 1984. We discussed the course of the extension of tumors and the reports in the literature were reviewed.